U.S. patent number 9,644,612 [Application Number 14/493,464] was granted by the patent office on 2017-05-09 for systems and methods for validating wind farm performance measurements.
This patent grant is currently assigned to General Electric Company. The grantee listed for this patent is General Electric Company. Invention is credited to Scott Charles Evans, Peter Alan Gregg, Satish G. Iyengar, Zhanpan Zhang.
United States Patent |
9,644,612 |
Evans , et al. |
May 9, 2017 |
Systems and methods for validating wind farm performance
measurements
Abstract
The present disclosure is directed to systems and methods for
validating and/or identifying wind farm performance measurements so
as to optimize wind farm performance. The method includes measuring
operating data from one or more wind turbines of the farm. Another
step includes generating a plurality of baseline models of
performance of the wind farm from at least a portion of the
operating data. Thus, each of the baseline models of performance is
developed from a different portion of operating data so as to
provide comparable models. The method also includes selecting an
optimal baseline model and comparing the optimal baseline model
with actual performance of the wind farm. In a particular
embodiment, the actual performance of the wind farm is determined
after one or more wind turbines of the wind farm is modified by one
or more upgrades.
Inventors: |
Evans; Scott Charles (Burnt
Hills, NY), Zhang; Zhanpan (Niskayuna, NY), Gregg; Peter
Alan (Niskayuna, NY), Iyengar; Satish G. (Niskayuna,
NY) |
Applicant: |
Name |
City |
State |
Country |
Type |
General Electric Company |
Schenectady |
NY |
US |
|
|
Assignee: |
General Electric Company
(Niskayuna, NY)
|
Family
ID: |
54238624 |
Appl.
No.: |
14/493,464 |
Filed: |
September 23, 2014 |
Prior Publication Data
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|
|
Document
Identifier |
Publication Date |
|
US 20160084233 A1 |
Mar 24, 2016 |
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H02J
3/381 (20130101); F03D 7/048 (20130101); H02J
3/00 (20130101); F03D 17/00 (20160501); F03D
9/257 (20170201); H02J 3/386 (20130101); F05D
2270/20 (20130101); Y02E 60/00 (20130101); F05D
2270/335 (20130101); Y02E 10/72 (20130101); H02J
2203/20 (20200101); Y02E 10/76 (20130101); H02J
2300/28 (20200101); Y04S 40/20 (20130101); H02J
2300/40 (20200101); F05B 2260/84 (20130101) |
Current International
Class: |
F03D
17/00 (20160101); F03D 9/00 (20160101); F03D
7/04 (20060101); H02J 3/00 (20060101); H02J
3/38 (20060101) |
Field of
Search: |
;73/1.27,1.28,112.01,112.03,147 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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1817496 |
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Oct 2013 |
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EP |
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2477968 |
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Aug 2011 |
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GB |
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2010000664 |
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Jan 2010 |
|
WO |
|
Other References
"Wind Turbines--Part 12-2: Power performance of electricity
producing wind turbines based on nacelle anemometry", Internet
Citation, Jul. 18, 2008, pp. 1-95. cited by applicant .
International Search Report and Written Opinion issued in
connection with corresponding PCT Application No. PCT/US2015/051186
dated Nov. 9, 2015. cited by applicant .
Article--Towards Wind Farm Performance Optimization through
Empirical Models, Aerospace Conference, 2014 IEEE, Mar. 1-8, 2014,
Evans at al., pp. 1-12. cited by applicant .
Abstract Only--Anticipatory Control of Wind Turbines with
Data-Driven Predictive Models, Energy Conversion, IEEE
Transactions, Sep. 2009, Kusiak et al., vol. 24, Issue 3, pp.
766-774. cited by applicant .
Abstract Only--Fuzzy Modeling Techniques and Artificial Keurai
Networks to Estimate Annual Energy Output of a Wind Turbine,
Renewable Energy, 2010, Jafarian et al., vol. 35, Issue 9, pp.
2098-2014. cited by applicant.
|
Primary Examiner: McCall; Eric S
Attorney, Agent or Firm: Joshi; Nitin N.
Claims
What is claimed is:
1. A method for validating one or more wind farm performance
measurements produced by one or more upgrades, the method
comprising: measuring operating data, via one or more sensors, from
one or more wind turbines of a wind farm; generating, via a
processor, a plurality of baseline models of performance of the
wind farm from at least a portion of the operating data, wherein
each of the baseline models of performance is developed from a
different portion of operating data from one or more wind turbines
of the wind farm; selecting, via the processor, an optimal baseline
model of performance from the plurality of baseline models; and,
comparing, via the processor, the optimal baseline model of
performance and an actual performance of the wind farm, wherein the
actual performance of the wind farm is determined after one or more
wind turbines of the wind farm are modified by the one or more
upgrades that have been installed for the one or more wind turbines
of the wind farm, and wherein comparing the optimal baseline model
of performance and the actual performance of the wind farm
comprises determining a difference between an optimal baseline
model of power output and an actual power output of the wind farm,
wherein the difference is reflective of a change in the power
output produced by the one or more upgrades.
2. The method of claim 1, wherein the performance measurements
comprise a power output of the wind farm.
3. The method of claim 1, wherein generating the plurality of
baseline models of performance of the wind farm from the operating
data further comprises: selecting one or more wind turbines for
each of the baseline models; selecting subsets of operating data
relating to each of the selected wind turbines; and creating each
of the baseline models from the subsets of operating data.
4. The method of claim 3, further comprising evaluating, via the
processor, each of the baseline models of performance of the wind
farm.
5. The method of claim 4, wherein evaluating each of the baseline
models further comprises comparing each of the baseline models to
additional subsets of operating data relating to each of the
selected wind turbines for each baseline model, wherein the
additional subsets of operating data are not used in creating the
baseline models.
6. The method of claim 3, further comprising eliminating baseline
models that contain the one or more wind turbines modified by the
one or more upgrades.
7. The method of claim 1, further comprising providing or
withholding the one or more upgrades to or from the wind turbines
of the wind farm in order to provide a basis of assessing farm
performance at a desired accuracy.
8. The method of claim 1, wherein the one or more upgrades comprise
any one of or a combination of the following: rotor blade chord
extensions, software upgrades, controls upgrades, hardware
upgrades, wake controls, aerodynamic upgrades, blade tip
extensions, vortex generators, winglets.
9. The method of claim 1, further comprising generating baseline
models of power output for a plurality of wind direction
sectors.
10. The method of claim 1, developing a long-term power
distribution by transforming a pre-specified long-term wind speed
distribution based on a reference power curve.
11. The method of claim 10, further comprising determining an
annual energy production (AEP) change of the wind farm in response
to the one or more upgrades by integrating the change in power
output produced by the one or more upgrades with respect to the
long-term power distribution.
12. The method of claim 1, wherein the one or more sensors comprise
any one of or a combination of the following: accelerometers,
pressure sensors, angle of attack sensors, vibration sensors,
Miniature Inertial Measurement Units (MIMUs), camera systems, fiber
optic systems, anemometers, wind vanes, Sonic Detection and Ranging
(SODAR) sensors, infra lasers, Light Detecting and Ranging (LIDAR)
sensors, radiometers, pitot tubes, rawinsondes.
13. A method for identifying one or more wind farm performance
measurements, the method comprising: measuring operating data, via
one or more sensors, from one or more wind turbines of the wind
farm; generating, via a processor, a plurality of baseline models
of power output of the wind farm from at least a portion of the
operating data, wherein each of the baseline models is developed
from a different portion of the operating data; evaluating, via the
processor, performance of each of the baseline models by comparing
each baseline model to an actual power output of the wind farm;
selecting, via the processor, an optimal baseline model based on
the evaluation; and identifying, via the processor, one or more
wind farm performance measurements of the wind farm based on the
optimal baseline model, wherein the wind farm performance
measurements are indicative of an error occurring in the wind
farm.
14. The method of claim 13, wherein generating the plurality of
baseline models of power output of the wind farm from the operating
data further comprises: selecting one or more wind turbines for
each of the baseline models; selecting subsets of operating data
relating to each of the selected wind turbines; and creating each
of the baseline models from the subsets of operating data.
15. The method of claim 14, wherein evaluating performance of each
of the baseline models of power output further comprises comparing
each of the baseline models to additional subsets of operating data
relating to each of the selected wind turbines for each baseline
model, wherein the additional subsets of operating data are not
used in creating the baseline models.
16. The method of claim 13, further comprising eliminating baseline
models that contain selected wind turbines having one or more
upgrades.
17. The method of claim 16, wherein the one or more upgrades
comprise any one of or a combination of the following: rotor blade
chord extensions, software upgrades, controls upgrades, hardware
upgrades, wake controls, aerodynamic upgrades, blade tip
extensions, vortex generators, winglets.
18. The method of claim 17, further comprising generating baseline
models for a plurality of wind direction sectors.
19. A system for validating one or more wind farm performance
measurements produced by one or more upgrades, the system
comprising: a plurality of sensors configured to measure operating
data from one or more wind turbines in a wind farm; and a
controller configured to perform a plurality of operations, the
plurality of operations comprising: generating a plurality of
baseline models of performance of the wind farm from at least a
portion of the operating data, wherein each of the baseline models
of performance is developed from a different portion of operating
data from one or more wind turbines of the wind farm, selecting an
optimal baseline model of performance from the plurality of
baseline models, and comparing the optimal baseline model of
performance and an actual performance of the wind farm, wherein the
actual performance of the wind farm is determined after one or more
wind turbines of the wind farm are modified by the one or more
upgrades that have been installed for the one or more wind turbines
of the wind farm, and wherein comparing the optimal baseline model
of performance and the actual performance of the wind farm
comprises determining a difference between an optimal baseline
model of power output and an actual power output of the wind farm,
wherein the difference is reflective of a change in the power
output produced by the one or more upgrades.
Description
FIELD OF THE INVENTION
The present disclosure relates generally to wind farms and, more
particularly, to systems and methods for validating wind farm
performance improvement measurements, e.g. power output.
BACKGROUND OF THE INVENTION
Wind power is considered one of the cleanest, most environmentally
friendly energy sources presently available, and wind turbines have
gained increased attention in this regard. A modern wind turbine
typically includes a tower, generator, gearbox, nacelle, and one or
more rotor blades. The rotor blades capture kinetic energy of wind
using known airfoil principles. For example, rotor blades typically
have the cross-sectional profile of an airfoil such that, during
operation, air flows over the blade producing a pressure difference
between the sides. Consequently, a lift force, which is directed
from a pressure side towards a suction side, acts on the blade. The
lift force generates torque on the main rotor shaft, which is
geared to a generator for producing electricity.
A plurality of wind turbines are commonly used in conjunction with
one another to generate electricity and are commonly referred to as
a "wind farm." Wind turbines on a wind farm typically include their
own meteorological monitors that perform, for example, temperature,
wind speed, wind direction, barometric pressure, and/or air density
measurements. In addition, a separate meteorological mast or tower
("met mast") having higher quality meteorological instruments that
can provide more accurate measurements at one point in the farm may
also be provided. The correlation of meteorological data with power
output provides the empirical determination of a "power curve" for
the individual wind turbines.
Typically, in a wind farm, each wind turbine attempts to maximize
its own power output while maintaining its fatigue loads within
desirable limits. To this end, each turbine includes a control
module, which attempts to maximize power output of the turbine in
the face of varying wind and grid conditions, while satisfying
constraints like sub-system ratings and component loads. Based on
the determined maximum power output, the control module controls
the operation of various turbine components, such as the
generator/power converter, the pitch system, the brakes, and the
yaw mechanism to reach the maximum power efficiency.
Often, while maximizing the power output of a single wind turbine,
neighboring turbines may be negatively impacted. For example,
downwind turbines may experience large wake effects caused by an
upwind turbine. Wake effects include reduction in wind speed and
increased wind turbulence downwind from a wind turbine typically
caused by the conventional operation of upwind turbines (i.e. for
maximum power output). Because of these wake effects, downwind
turbines receive wind at a lower speed, drastically affecting their
power output (as power output is proportional to wind speed).
Moreover, wind turbulence negatively affects the fatigue loads
placed on the downwind turbines, and thereby affects their life (as
life is proportional to fatigue loads). Consequently, maximum
efficiency of a few wind turbines may lead to sub-optimal power
output, performance, or longevity of other wind turbines in the
wind farm. Thus, modern control technologies attempt to optimize
the wind farm power output rather than the power outputs of each
individual wind turbine.
In addition, there are many products, features, and/or upgrades
available for wind turbines and/or wind farms so as to increase
power output or annual energy production (AEP) of the wind farm.
Once an upgrade has been installed, it is advantageous to
efficiently determine various wind turbine performance improvement
measurements so as to verify the benefit of the upgrade. For
example, a typical method for assessing wind turbine performance
measurements is to baseline power against wind speed as assessed by
the turbine nacelle anemometer. The nacelle anemometer approach,
however, is sometimes hindered due to imprecision of nacelle
anemometer measurements and the projection of these measurements
into AEP estimates. Further, such an approach may be less preferred
than use of an external met mast in front of a wind turbine, but is
in widespread use due to the generally prohibitive cost of the met
mast approach. In addition, even when nacelle anemometers are
calibrated correctly, individual wind power curve methods are not
able to discern the benefit of upgrades, such as wake minimization
technologies, that can create more wind for the farm to use. In
view of the aforementioned issues, still another approach for
assessing wind turbine performance measurements is to baseline
performance against a control turbine in close proximity to a
turbine of interest. Such an approach, however, is subject to the
availability of the control turbine and further inaccuracies due to
reliance on a single, more distant sensor. Thus, it is difficult to
show the benefit of upgrades to individual turbines.
Accordingly, there is a need for improved systems and methods for
validating wind farm performance improvement measurements that
address the aforementioned issues. Thus, the present disclosure is
directed to systems and methods for baselining wind turbine
performance measurements using multi-feature estimation that
normalizes AEP uncertainty estimates.
BRIEF DESCRIPTION OF THE INVENTION
Aspects and advantages of the invention will be set forth in part
in the following description, or may be obvious from the
description, or may be learned through practice of the
invention.
In one aspect, the present disclosure is directed to a method for
validating wind farm performance measurements after one or more
upgrades have been installed. The method includes measuring
operating data, via one or more sensors, from one or more wind
turbines of the wind farm. Another step includes generating, via a
processor, a plurality of baseline models of performance of the
wind farm (e.g. power output) from at least a portion of the
operating data. Thus, each of the baseline models of performance is
developed from a different portion of operating data so as to
provide comparable models. The method also includes selecting, via
the processor, an optimal baseline model of performance from the
plurality of baseline models. Still another step includes
comparing, via the processor, the optimal baseline model of
performance and an actual performance of the wind farm, wherein the
actual performance of the wind farm is determined after one or more
wind turbines of the wind farm are modified by the one or more
upgrades.
In another aspect, the present disclosure is directed to a method
for identifying one or more wind farm performance measurements. The
method includes measuring operating data, via one or more sensors,
from one or more wind turbines of the wind farm. Another step
includes generating, via a processor, a plurality of baseline
models of power output of the wind farm from at least a portion of
the operating data, wherein each of the baseline models is
developed from a different portion of the operating data. Yet
another step includes evaluating performance of each of the
baseline models by comparing each baseline model to an actual power
output of the wind farm. A further step includes selecting an
optimal baseline model based on the evaluation. Thus, the method
also includes identifying, via the processor, one or more wind farm
performance measurements of the wind farm based on the optimal
baseline model, wherein the wind farm performance measurements are
indicative of an error occurring in the wind farm.
In yet another aspect, the present disclosure is directed to a
system for validating wind farm performance measurements produced
by one or more upgrades. The system includes a plurality of sensors
configured to measure operating data from one or more wind turbines
in a wind farm and a controller configured to perform one or more
operations. The operations include, at least, generating a
plurality of baseline models of performance of the wind farm from
at least a portion of the operating data, wherein each of the
baseline models is developed from a different portion of the
operating data. Further operations include selecting an optimal
baseline model of performance from the plurality of baseline
models, and comparing the optimal baseline model of performance and
an actual performance of the wind farm, wherein the actual
performance of the wind farm is determined after one or more wind
turbines of the wind farm are modified by the one or more upgrades.
These and other features, aspects and advantages of the present
invention will become better understood with reference to the
following description and appended claims. The accompanying
drawings, which are incorporated in and constitute a part of this
specification, illustrate embodiments of the invention and,
together with the description, serve to explain the principles of
the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
A full and enabling disclosure of the present invention, including
the best mode thereof, directed to one of ordinary skill in the
art, is set forth in the specification, which makes reference to
the appended figures, in which:
FIG. 1 illustrates a perspective view of one embodiment of a wind
farm according to the present disclosure;
FIG. 2 illustrates a perspective view of one embodiment of a wind
turbine according to the present disclosure;
FIG. 3 illustrates a block diagram of one embodiment of a
controller of a wind turbine and/or or wind farm according to the
present disclosure;
FIG. 4 illustrates a graph of one embodiment of the percent (%)
uncertainty of the AEP change in response to one or more upgrades
as a function of the number of wind turbines according to the
present disclosure;
FIG. 5 illustrates a flow diagram of one embodiment of a method for
validating wind farm performance measurements according to the
present disclosure;
FIG. 6 illustrates a graph of one embodiment of the mean power
output for a plurality of statistical algorithms according to the
present disclosure;
FIG. 7 illustrates a graph of another embodiment of the mean power
output for a plurality of statistical algorithms using different
features according to the present disclosure;
FIG. 8 illustrates a graph of one embodiment of the power output
versus time for a plurality of baseline models according to the
present disclosure;
FIG. 9 illustrates a graph of one embodiment of the power output
versus time for an optimal baseline model according to the present
disclosure;
FIG. 10 illustrates a layout of one embodiment of a wind farm
particularly illustrating selected wind turbines of one of the
baseline models according to the present disclosure;
FIG. 11 illustrates a graph of one embodiment of the mean residual
between actual and predicted power according to the present
disclosure;
FIG. 12 illustrates a graph of one embodiment of actual and
predicted power output as a function of wind sector according to
the present disclosure;
FIG. 13 illustrates one embodiment a plurality of graphs of
long-term wind speed distribution and a reference power curve used
to integrate the power change with respect to a long-term power
distribution according to the present disclosure; and
FIG. 14 illustrates a flow diagram of another embodiment of a
method for validating wind farm performance measurements according
to the present disclosure.
DETAILED DESCRIPTION OF THE INVENTION
Reference now will be made in detail to embodiments of the
invention, one or more examples of which are illustrated in the
drawings. Each example is provided by way of explanation of the
invention, not limitation of the invention. In fact, it will be
apparent to those skilled in the art that various modifications and
variations can be made in the present invention without departing
from the scope or spirit of the invention. For instance, features
illustrated or described as part of one embodiment can be used with
another embodiment to yield a still further embodiment. Thus, it is
intended that the present invention covers such modifications and
variations as come within the scope of the appended claims and
their equivalents.
Generally, the present disclosure is directed to improved systems
and methods for validating or identifying wind farm performance
measurements in a wind farm. For example, in one embodiment, the
system is configured to validate wind farm performance
measurements, i.e. power output, in response to one or more
upgrades installed within the wind farm so as to optimize wind farm
performance. Alternatively, the system may be configured to
identify wind farm performance measurements (i.e. problems or
errors) in a wind farm, such as, for example misconfigurations,
material or software failures, and/or other problematic
circumstances causing sub-par performance of the wind farm.
In various embodiments, a farm controller is configured to estimate
an annual energy production (AEP) change after an upgrade is
installed for one or more wind turbines (e.g. turbine(s) of
interest) of the wind farm. More specifically, the farm controller
is configured to receive and store operating data collected from a
plurality of wind turbines (including the turbine(s) of interest)
of the wind farm measured by one or more sensors. The farm
controller then generates a plurality of baseline models of
performance of the wind farm (e.g. power output) from the operating
data. For example, in one embodiment, the farm controller selects a
plurality of subsets of wind turbines from the wind farm to form
the baseline models that do not include the turbine(s) of interest
and selects the model that achieves the best accuracy, namely the
optimal baseline model. The farm controller then compares the
optimal baseline model of performance with the actual performance
of the wind farm after one or more upgrades have been installed.
For example, in one embodiment, the controller compares the optimal
baseline model of power output with the actual power output and
determines the associated uncertainty of the power output change.
It should be understood that the upgrades may include any suitable
upgrade now known or later developed in the art, including but not
limited to rotor blade chord extensions, software upgrades,
controls upgrades, hardware upgrades, wake controls, aerodynamic
upgrades, blade tip extensions, vortex generators, winglets, or
similar. Accordingly, the farm controller is configured to validate
wind farm performance improvements (such as improvements in wind
farm power) that occur in response to at least one upgrade being
installed.
The present disclosure has many advantages not present in the prior
art. For example, the present disclosure leverages and fuses
accurate available sensor data using machine learning algorithms.
That is, the more relevant, good quality sensors used, and the more
data pooled in like conditions, the lower the predictive error of
the optimal baseline model will be. Thus, accuracy of wind farm
performance improvement measurements may be improved and associated
costs and times may be reduced.
Referring now to the drawings, FIG. 1 illustrates an exemplary
embodiment of a wind farm 100 containing a plurality of wind
turbines 102 according to aspects of the present disclosure. The
wind turbines 102 may be arranged in any suitable fashion. By way
of example, the wind turbines 102 may be arranged in an array of
rows and columns, in a single row, or in a random arrangement.
Further, FIG. 10 illustrates an example layout of one embodiment of
the wind farm 100. Typically, wind turbine arrangement in a wind
farm is determined based on numerous optimization algorithms such
that AEP is maximized for corresponding site wind climate. It
should be understood that any wind turbine arrangement may be
implemented, such as on uneven land, without departing from the
scope of the present disclosure.
In addition, it should be understood that the wind turbines 102 of
the wind farm 100 may have any suitable configuration, such as for
example, as shown in FIG. 2. As shown, the wind turbine 102
includes a tower 114 extending from a support surface, a nacelle
116 mounted atop the tower 114, and a rotor 118 coupled to the
nacelle 16. The rotor includes a rotatable hub 120 having a
plurality of rotor blades 112 mounted thereon, which is, in turn,
connected to a main rotor shaft that is coupled to the generator
housed within the nacelle 116 (not shown). Thus, the generator
produces electrical power from the rotational energy generated by
the rotor 118. It should be appreciated that the wind turbine 102
of FIG. 2 is provided for illustrative purposes only. Thus, one of
ordinary skill in the art should understand that the invention is
not limited to any particular type of wind turbine
configuration.
As shown generally in the figures, each wind turbine 102 of the
wind farm 100 may also include a turbine controller 104
communicatively coupled to a farm controller 108. Moreover, in one
embodiment, the farm controller 108 may be coupled to the turbine
controllers 104 through a network 110 to facilitate communication
between the various wind farm components. The wind turbines 102 may
also include one or more sensors 105 configured to monitor various
operating, wind, and/or loading conditions of the wind turbine 102.
For instance, the one or more sensors may include blade sensors for
monitoring the rotor blades 112; generator sensors for monitoring
generator loads, torque, speed, acceleration and/or the power
output of the generator; wind sensors for monitoring the one or
more wind conditions; and/or shaft sensors for measuring loads of
the rotor shaft and/or the rotational speed of the rotor shaft.
Additionally, the wind turbine 102 may include one or more tower
sensors for measuring the loads transmitted through the tower 114
and/or the acceleration of the tower 114. In various embodiments,
the sensors may be any one of or combination of the following:
accelerometers, pressure sensors, angle of attack sensors,
vibration sensors, Miniature Inertial Measurement Units (MIMUs),
camera systems, fiber optic systems, anemometers, wind vanes, Sonic
Detection and Ranging (SODAR) sensors, infra lasers, Light
Detecting and Ranging (LIDAR) sensors, radiometers, pitot tubes,
rawinsondes, other optical sensors, and/or any other suitable
sensors.
Referring now to FIG. 3, there is illustrated a block diagram of
one embodiment of suitable components that may be included within
the farm controller 108 and/or the turbine controller(s) 104 in
accordance with aspects of the present disclosure. As shown, the
controller 108 may include one or more processor(s) 150 and
associated memory device(s) 152 configured to perform a variety of
computer-implemented functions (e.g., performing the methods,
steps, calculations and the like and storing relevant data as
disclosed herein). Additionally, the controller 108 may also
include a communications module 154 to facilitate communications
between the controller 108 and the various components of the wind
turbine 102. Further, the communications module 154 may include a
sensor interface 156 (e.g., one or more analog-to-digital
converters) to permit signals transmitted from one or more sensors
103, 105, 107, 109 (such as the sensors described herein) to be
converted into signals that can be understood and processed by the
processors 150. It should be appreciated that the sensors 103, 105,
107, 109 may be communicatively coupled to the communications
module 154 using any suitable means. For example, as shown, the
sensors 103, 105, 107, 109 are coupled to the sensor interface 156
via a wired connection. However, in other embodiments, the sensors
103, 105, 107, 109 may be coupled to the sensor interface 156 via a
wireless connection, such as by using any suitable wireless
communications protocol known in the art.
As used herein, the term "processor" refers not only to integrated
circuits referred to in the art as being included in a computer,
but also refers to a controller, a microcontroller, a
microcomputer, a programmable logic controller (PLC), an
application specific integrated circuit, and other programmable
circuits. Additionally, the memory device(s) 152 may generally
comprise memory element(s) including, but not limited to, computer
readable medium (e.g., random access memory (RAM)), computer
readable non-volatile medium (e.g., a flash memory), a floppy disk,
a compact disc-read only memory (CD-ROM), a magneto-optical disk
(MOD), a digital versatile disc (DVD) and/or other suitable memory
elements. Such memory device(s) 152 may generally be configured to
store suitable computer-readable instructions that, when
implemented by the processor(s) 150, configure the controller 108
to perform various functions as described herein. Moreover, the
network 110 that couples the farm controller 108, the turbine
controllers 104, and the wind sensors 106 in the wind farm 100 may
include any known communication network such as a wired or wireless
network, optical networks, and the like. In addition, the network
110 may be connected in any known topology, such as a ring, a bus,
or hub, and may have any known contention resolution protocol
without departing from the art. Thus, the network 110 is configured
to provide data communication between the turbine controller(s) 104
and the farm controller 108 in near real time.
In addition, the farm controller 108 is configured to obtain or
collect data from the sensors 103, 105, 107, 109 and/or other data
sources such as turbine empirical models. Employing these inputs,
the farm controller 108 is configured to determine one or more
baseline models of performance of the wind farm 100 that can be
used to validate farm-level performance for the wind farm 100 (e.g.
farm-level power output). More specifically, the farm controller
108 baselines wind turbine performance using multi-feature
estimation that normalizes AEP uncertainty estimates and does not
rely solely on nacelle anemometer estimates or expensive additional
sensors. In one embodiment, for example, the present disclosure
provides a unified paradigm which leverages and fuses the best
sensors available using machine learning algorithms. Thus, the farm
controller 108 is configured to leverage big data and numerous
sensors to improve accuracy of estimates regardless of the
machine-learning model used. For example, as shown in FIG. 4, as
the number of wind turbines 102 used to collect operating data
increases, the percent (%) uncertainty decreases. In addition, as
shown by the varying line types, as the time period for collecting
data increases (e.g. from minutes to years), the % uncertainty
decreases. Thus, the more relevant, good quality sensors used, and
the more data pooled in like conditions the lower the predictive
error of the model will be.
Referring now to FIG. 5, a simplified flow chart illustrating one
embodiment of a method 200 for validating performance improvement
measurements of the wind farm 100 according to the present
disclosure is illustrated. As shown at 202, the farm controller 108
may include a global repository configured to collect and store the
operating data collected from the sensors 103, 105, 107, 109. It
should be understood that the wind turbine operating data may
include any relevant operating data concerning the wind turbines
102 including but not limited to a pitch angle, generator speed,
power output, torque output, air density, temperature, pressure,
wind speed, wind peaks, wind turbulence, wind shear, wind
direction, or similar.
At 204, the operating data may be filtered to provide filtered data
206. For example, in one embodiment, the data may be filtered for a
variety of reasons including but not limited to: when one of the
wind turbines 102 is not fully operational during a certain time
interval (e.g. a 10-minute interval), when curtailment is detected,
and/or when data points have very low wind speeds (e.g. less than 2
meters/second). It should be understood that the data may be
filtered using any other suitable filter parameters in addition to
those specifically described herein.
At 208, the data may be optionally synchronized or harmonized so as
to establish consistency among the data collected from multiple
sources. Further, at 210, the farm controller can be configured to
impute data when missing values exist in the historical data. For
example, the initial filtering described above may create gaps in
the operating data. Since various embodiments of the present
disclosure require estimating the power from one or more wind
turbine(s) of interest and using information from neighboring
turbines, the absence of measurements at a given time interval
requires that the corresponding data record be completely removed,
thereby leading to a significant loss of data. Thus, the farm
controller 108 is configured to impute the missing data, i.e.
substitute missing values with estimated values to obtain a more
complete dataset for modeling and analysis. It should be understood
that any imputation methods known in the art may be used. For
example, in one embodiment, the missing data may be imputed using
the k-nearest neighbor algorithm. Such an algorithm replaces
missing data of a given turbine with a weighted mean of
measurements from its k nearest-neighbors. In certain embodiments,
the weights are inversely proportional to its Euclidean distance
from the neighboring turbines.
In additional embodiments (e.g. when using wind speed data from
neighboring turbines), linearization of the operating data may be
useful prior to incorporation into the power model. For example, as
shown at 212, a Bayesian power curve methodology may be utilized to
linearize the operating data to produce power estimates for input
into modeling algorithms. At 214, linear as well as non-linear data
are integrated to provide integrated data 216.
At 218, one or more statistical models are built to estimate a
performance measurement improvement (e.g. power output) from an
individual wind turbine 102. For example, in a particular
embodiment, stepwise linear regression may be utilized to estimate
power output from an individual wind turbine 102. Generally,
stepwise linear regression adds or removes features one at a time
in an attempt to get the best regression model without over
fitting. Further, stepwise regression typically has two variants,
including forward and backward regression, both of which are within
the scope and spirit of the invention. For example, forward
stepwise regression is a step-by-step process of building a model
by successive addition of predictor variables. At each step, models
with and without a potential predictor variable are compared, and
the larger model is accepted only if it leads to a significantly
better fit to the data. Alternatively, backward stepwise regression
starts with a model with all predictors and removes terms that are
not statistically significant in terms of modeling a response
variable.
Another statistical method that may be used to validate performance
measurement improvement (e.g. power output) of the wind farm 100 is
a least absolute shrinkage and selection operator (LASSO)
algorithm. Generally, a LASSO algorithm minimizes the residual sum
of squares subject to a constraint that the sum of the absolute
value of the coefficients is smaller than a constant. Still another
statistical algorithm that may be used to validate the performance
measurement improvements from the wind farm 100 is a M5 Prime (M5P)
algorithm, which is a tree-based regression algorithm that is
effective in many domains. For example, whereas stepwise linear
regression produces a single global linear model for the data, tree
based regression algorithms perform logical tests on features to
form a tree structure. Generally, the M5P algorithm utilizes a
linear regression model at each node of the tree, providing more
specialized models.
Referring now to FIG. 6, sample results from the statistical
algorithms used to validate power output, namely stepwise linear
regression (line 224), LASSO (line 226), and M5P (line 228), are
compared. As shown, the stepwise algorithm 224 performs as well as
the more complicated LASSO (line 226) and M5P (line 228) algorithms
for a particular turbine, with some variation. Further, as shown,
the LASSO (line 226) and M5P (line 228) algorithms provide similar
power estimates for the wind farm 100. In some months, however, M5P
(line 228) performed best, whereas in other months, LASSO 226
performed better. It should be understood that the various
statistical models described herein are provided for example only
and any other statistical models are within the spirit and scope of
the invention.
Referring now to FIG. 7, the root mean squared error (RMSE) of
predicted power divided by mean power produced in a given month of
data for various models are illustrated, which can be interpreted
as a measure of prediction error normalized by output power. In
certain embodiments, utilization of approximately one months' worth
of training data provides effective means of predicting a turbine's
power for a 100-turbine farm, however, it should be understood that
any amount of data may be used to develop each of the models. For
example, as shown in the illustrated embodiment, a wind turbine 102
trained using January data may generate approximately 5% error on
the training when all features, including the Bayesian Power Curve
power estimate, are included in the feature set (line 230).
However, when only wind speed and power are used (line 232), the
error on the training data is about 8%, moving to 15% when only
power from other turbines is used (line 234). If only wind speed is
used in the model (line 236), the error in predicting a 10-minute
interval from the model against training data is over 23%. When
these models trained in January are applied to test data in the
other months of the year the error characteristic is as shown.
Thus, as shown in the illustrated embodiment, the optimal results
were obtained when the onboard nacelle anemometer and the Bayesian
Power Curve Estimate were included as features (line 230).
Referring now to FIGS. 8 and 9, the present disclosure includes
comparing and analyzing the plurality of baseline models and
selecting the model that provides the best or most accurate
performance to validate farm power output improvement in response
to an upgrade, i.e. the optimal baseline model. For example, as
shown in FIG. 8, the farm controller 108 measures a plurality of
operating data from one or more subsets of wind turbines 102 within
the wind farm 100. The controller 108 can then generate a plurality
of baseline models for each of the subsets of data. In certain
embodiments, the controller 108 is configured to validate each of
the baseline models by applying new data to each model (that was
not used in creating the baseline models) to determine how well
each model predicted total farm power output. For example, in one
embodiment, a first operating data set may include a first subset
and a second subset. Thus, one of the baseline models may be
generated using the first subset and then validated using the
second subset. For example, in a wake controls embodiment, a
baseline model (i.e. where wake controls are not in effect) may be
exercised against new data where wake controls are also not in
effect such that wind farm power output can be predicted with a
small margin of error. In alternative embodiments, the controller
108 can validate the baseline models based on training data alone
such that verification using new data (e.g. the second subset) is
not necessary.
In another embodiment, the farm controller 108 may also eliminate
baseline models that contain one or more wind turbines that have
been modified by one or more upgrades. In still additional
embodiments, the farm controller 108 can strategically provide or
withhold (e.g. turn on and off) certain upgrades or modifications
(e.g. wake controls) from one or more wind turbines in the wind
farm in order to provide a basis for assessing farm performance at
a desired accuracy. Further, the extent to which modifications are
left in place or removed gives the ability to trade off validation
accuracy for farm performance improvement.
Referring back to FIG. 5, once the baseline models have been built
and the optimal baseline model chosen, the AEP uncertainty
evaluation 220 begins to determine the AEP uncertainty 222.
Applying the trained or optimal model to the test data, the
controller 108 can determine the baseline predicted power that is
representative of the power estimate if no upgrade has been
applied. Further, the residual power is defined as the difference
between the observed or actual power and the baseline predicted
power, which representative of the power change due to the upgrade
and which is used to evaluate the AEP change. For example, as shown
in FIG. 9, actual power 238 is compared with predicted power 242 as
determined by the optimal baseline model. In the illustrated
embodiment, the optimal baseline model is based on the predicted
power 242 as determined by sensors from two of the wind turbines
102. In addition, line 240 represents the estimate of total farm
power when half of the wind turbines 102 are used in the model to
predict power. As shown, the predicted power 242 as determined by
the optimal model is similar to the actual power 238 as determined
by one or more sensors.
Referring now to FIG. 10, the optimal baseline model is then
applied to the wind farm 100. More specifically, as shown, the farm
controller 108 determines the control sensors for a given sample
within the set of control turbines (as indicated by markers 252)
and then applies the optimal baseline model thereto. The farm
controller 108 can then model the error 244 or residual between
actual and predicted power to determine the performance
change/uncertainty as shown in FIG. 11. It should be understood
that accuracy of the baseline models generally improves with more
data although any amount of data may be used to build the model. In
certain embodiments, the controller 108 may also determine the mean
error 246 between the actual and predicted power to determine a
mean uncertainty value.
In additional embodiments, as shown in FIGS. 12 and 13, the farm
controller 108 can calculate the AEP change before and after an
upgrade by integrating the power change with respect to a long-term
power distribution 304. For example, in one embodiment, the farm
controller 108 transforms a pre-specified long term wind speed
distribution 300 based on a reference power curve 302 as shown. In
addition, the controller 108 may determine the AEP as a function of
wind sector as shown in FIG. 12. More specifically, as shown, line
248 represents AEP with wake controls, whereas line 250 represents
AEP without wake controls. Thus, the controller 108 may be
configured to compute the baseline models for every possible sector
of wind direction. For example, in one embodiment, the controller
108 may determine a set of models for the wind sector having a
median wind direction of 10 to 20 degrees. The farm controller 108
can then train the models on data where the median wind direction
is between 10 and 20 degrees and use the models to predict farm
output when the wind direction is between 10 to 20 degrees. In such
an embodiment with 10-degree wind sectors, there are 36 different
model sets, each with a model of farm output using every
permutation and combination of sensor inputs. Still other wind
sectors could be used, for example, as shown in FIG. 12 (i.e.
20-degree sectors), in which case, there would be 18 different
model sets, and so on.
Referring now to FIG. 14, a flow diagram of a method 300 for
validating wind farm performance improvement measurements produced
by one or more upgrades is illustrated. At 302, the method 300
includes measuring operating data, via one or more sensors, from
one or more wind turbines of a wind farm. At 304, the method 300
includes generating a plurality of baseline models of performance
of the wind farm from at least a portion of the operating data,
wherein each of the baseline models of performance is developed
from a different set of operating data from one or more wind
turbines of the wind farm. At 306, the method 300 includes
selecting, via the processor, an optimal baseline model of
performance from the plurality of baseline models. At 308, the
method 300 includes comparing the optimal baseline model of
performance and an actual performance of the wind farm, wherein the
actual performance of the wind farm is determined after the one or
more upgrades are installed.
As mentioned, the system and method as described herein may also be
configured to identify one or more performance measurements (e.g.
errors) of the wind farm, as well as performance improvements. As
described herein, the term "error" is meant to encompass its
ordinary meaning as known in the art, as well as misconfigurations,
material or software failures, or other problematic circumstances
that may cause sub-par performance of the wind farm. In still
additional embodiments, an error may be occurring where the wind
farm is performing below baseline expectations for a variety of
reasons. In one implementation, for example, the information from
the farm validation methodology can be used to determine when a
wind turbine in the wind farm or the entire wind farm is not
configured correctly or has suffered from a casualty.
This written description uses examples to disclose the invention,
including the best mode, and also to enable any person skilled in
the art to practice the invention, including making and using any
devices or systems and performing any incorporated methods. The
patentable scope of the invention is defined by the claims, and may
include other examples that occur to those skilled in the art. Such
other examples are intended to be within the scope of the claims if
they include structural elements that do not differ from the
literal language of the claims, or if they include equivalent
structural elements with insubstantial differences from the literal
languages of the claims.
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